Understanding Moment of Inertia and Bending Stress in Physics Forums

[falah alajmi]

hi all ,

I am a new member in physics forums and I hope I can help and get benefit from this forums .

I would ask anyone knows about the moment of inertia cos i have not study it before and I have to know it to solve a bending stress problem ..

when I used the moment of inertia for rectangle as 1/3 bh^3 and when I use it as 1/12 bh^3

as I now I use the first one when the neutral axises pass through the centroid and the second one when it not pass through the centroid .. but how can I know if the neutral axises pass through the centre of gravity or not ?


sincerely
falah alajmi

 

[falah alajmi]

there is no one knows the answer